Flame retardant compositions and processes for preparation thereof

ABSTRACT

This disclosure provides a composition comprising one or more substrate materials (e.g., polymers, rubbers, paper pulps, textiles, or polymer foams) and a flame retardant composition. The flame retardant composition includes at least one flame retardant salt (e.g., an ammonium salt of phosphoric acid such as water soluble ammonium polyphosphate), a nitrogen-containing compound (e.g., urea), and optionally water. This disclosure also provides a process for preparing the flame retardant composition, a process for imparting flame retardancy to a substrate material, and an intumescent process for forming an insulating protective layer on a substrate. This disclosure further provides fire retardant articles and processes for preparing fire retardant articles.

RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application Ser.No. 62/425,202, filed on Nov. 22, 2016, which is incorporated herein byreference in its entirety.

BACKGROUND 1. Field of the Disclosure

This disclosure relates to flame retardant compositions and water-basedcompositions, processes for preparing flame retardant compositions andwater-based compositions, processes for the production of an extrudedarticles, processes for imparting flame retardancy to substratematerials, intumescent processes for forming an insulating protectivelayer on a substrate, and fire retardant articles.

2. Description of the Related Art

Flame retardants are a key component in reducing the devastating impactof fires on people, property and the environment. They are added to ortreat potentially flammable materials, including textiles and plastics.The term “flame retardant” refers to a function, not a family ofchemicals. A variety of different chemicals, with different propertiesand structures, act as flame retardants and these chemicals are oftencombined for effectiveness.

Flame retardants are added to different materials or applied as atreatment to materials (e.g., textiles, plastics) to prevent fires fromstarting, limit the spread of fire, and minimize fire damage. Some flameretardants work effectively on their own; others act as “synergists” toincrease the fire protective benefits of other flame retardants. Avariety of flame retardants is necessary because materials that need tobe made fire-resistant are very different in their physical nature andchemical composition, so they behave differently during combustion. Theelements in flame retardants also react differently with fire. As aresult, flame retardants have to be matched appropriately to each typeof material. Flame retardants work to stop or delay fire, but, dependingon their chemical makeup, they interact at different stages of the firecycle.

In the fire cycle, the initial ignition source can be any energy source(e.g., heat, incandescent material, a small flame). The ignition sourcecauses the material to burn and decompose (pyrolysis), releasingflammable gases. If solid materials do not break down into gases, theyremain in a condensed phase. During this phase, they will slowly smolderand, often, self-extinguish, especially if they “char,” meaning thematerial creates a carbonated barrier between the flame and theunderlying material. In the gas phase, flammable gases released from thematerial are mixed with oxygen from the air. In the combustion zone, orthe burning phase, fuel, oxygen and free radicals combine to createchemical reactions that cause visible flames to appear. The fire thenbecomes self-sustaining because, as it continues to burn the material,more flammable gases are released, feeding the combustion process.

When flame retardants are present in the material, they can act in threekey ways to stop the burning process. They may work to: disrupt thecombustion stage of a fire cycle, including avoiding or delaying“flashover,” or the burst of flames that engulfs a room and makes itmuch more difficult to escape; limit the process of decomposition byphysically insulating the available fuel sources from the materialsource with a fire-resisting “char” layer; and/or dilute the flammablegases and oxygen concentrations in the flame formation zone by emittingwater, nitrogen or other inert gases.

Many flame retardants are limited in their end use applications becauseof physical constraints (e.g., liquids or solids). For example, liquidflame retardant compositions must be topically sprayed onto finishedproducts to impart flame retardancy to those products. Their applicationis limited to finished products.

It would be desirable in the art to have flame retardants that are notlimited in their end use applications because of physical constraints(e.g., liquids or solids). In particular, it would be desirable to haveflame retardant compositions that are effective as solids and liquids,and thus greatly expand their potential end use applications. Further,in particular, it would be desirable to have flame retardantcompositions that are effective as solids (e.g., powders) and can beformulated (e.g., extruded) with unfinished products, and also that areeffective as liquids (e.g., water based solutions) and can be sprayedonto finished products. Still further, it would be desirable to haveflame retardant compositions that are not corrosive to metals.

SUMMARY

This disclosure relates in part to a composition comprising one or moresubstrate materials and a flame retardant powder composition. The flameretardant powder composition comprises at least one flame retardantsalt, and a nitrogen-containing compound.

This disclosure also relates in part to a composition comprising one ormore substrate materials and a flame retardant composition. The flameretardant composition comprises at least one flame retardant salt, anitrogen-containing compound, and water.

This disclosure further relates in part to a composition comprising oneor more substrate materials and a flame retardant composition. The flameretardant composition comprises at least one flame retardant salt, anitrogen-containing compound, and optionally water. The at least oneflame retardant salt comprises water soluble ammonium polyphosphate(APP), and the nitrogen-containing compound comprises urea.

This disclosure yet further relates in part to a one or more substratematerials and a flame retardant composition. The flame retardantcomposition comprises at least one flame retardant salt, anitrogen-containing compound, and optionally water. The at least oneflame retardant salt comprises water soluble ammonium polyphosphate(APP), ammonium dihydrogen phosphate (MAP), and di-ammonium hydrogenphosphate (DAP); and the nitrogen-containing compound comprises urea.

This disclosure also relates in part to a composition comprising one ormore substrate materials and a flame retardant composition. The flameretardant composition comprises at least one flame retardant salt, anitrogen-containing compound, and optionally water. The at least oneflame retardant salt comprises water soluble ammonium polyphosphate(APP) and ammonium bromide; and the nitrogen-containing compoundcomprises urea.

This disclosure further relates in part to a composition comprising oneor more substrate materials and a flame retardant composition. The flameretardant composition comprises at least one flame retardant salt,optionally a nitrogen-containing compound, and optionally water. The atleast one flame retardant salt comprises water soluble ammoniumpolyphosphate (APP).

This disclosure still further relates in part to a flame retardantcomposition comprising at least one flame retardant salt, optionally anitrogen-containing compound, and optionally water. The at least oneflame retardant salt comprises water soluble ammonium polyphosphate(APP). The water soluble ammonium polyphosphate (APP) has a totalnitrogen as N from about 5 to about 15 weight percent, and a totalphosphorus as P₂O₅ from about 30 to about 40 weight percent, based onthe total weight of the ammonium polyphosphate. The water solubleammonium polyphosphate (APP) has a density from about 1.75 to about 1.90g/cm³, a water solubility of greater than about 60 g/100 ml, and a pHfrom about 6.5 to about 8.5.

This disclosure also relates in part to an article formed from acomposition. The composition comprises one or more substrate materialsand a flame retardant composition. The flame retardant compositioncomprises at least one flame retardant salt, a nitrogen-containingcompound, and optionally water. The article comprises (i) a polymerarticle selected from a polymer molding, a polymer film, a polymerfilament and a polymer fiber; or (ii) an extrusion article formed byextrusion, injection molding, or a combination thereof.

This disclosure further relates in part to a process for the productionof an extruded article. The process comprises (a) heating a polymer toform a polymer melt; (b) adding a flame retardant powder composition tothe polymer melt to form a flame retardant polymer melt; and (c)extruding the flame retardant polymer melt to give an extruded article.The flame retardant composition comprises at least one flame retardantsalt, and a nitrogen-containing compound.

This disclosure still further relates in part to a process for impartingflame retardancy to a substrate material. The process comprises addingto the substrate material a flame retardant composition. The flameretardant composition comprises at least one flame retardant salt, anitrogen-containing compound, and optionally water.

This disclosure also relates in part to a process for preparing a flameretardant powder composition. The process comprises (a) adding to acontainer at least one flame retardant salt, and a nitrogen-containingcompound; and (b) mixing the contents of the container to give adispersed mixture or dissolved solution comprising the flame retardantcomposition.

This disclosure further relates in part to a process for preparing aflame retardant water based composition. The process comprises (a)adding to a container at least one flame retardant salt, anitrogen-containing compound, and water; and (b) mixing the contents ofthe container to give a dispersed mixture or dissolved solutioncomprising the flame retardant composition.

This disclosure yet further relates in part to an intumescent processfor forming an insulating protective layer on a substrate. The processcomprises: (a) providing a flame retardant composition comprising atleast one flame retardant salt, a nitrogen-containing compound, andoptionally water, in which the at least one flame retardant saltcomprises an ammonium salt of phosphoric acid, and thenitrogen-containing compound comprises urea; (b) heating the ammoniumsalt of phosphoric acid to give an inorganic acid; (c) carbonizing theinorganic acid with a polyalcohol present in the substrate; (d)hydrolyzing the urea to give ammonia and reacting the ammonia to givenitrogen gas; (e) foaming the mixture of the carbonized inorganic acidand the nitrogen gas; and (f) solidifying the foam through one or morecross linking reactions to form the insulating protective layer on thesubstrate.

The present disclosure provides many advantages including, but notlimited to (1) the advantage of a water-based system over a solventsystem in terms of transportation (not classified as dangerous goods)and economic costs; (2) the advantage of a water-based system over asolvent system in terms of ease to form new systems with addedperformance other than flame protection, by mixing with many watersoluble additives; (3) other than Ready-To-Use (RTU), the advantages ofhaving the flame retardant in powder form rather than in liquid form (noworrying about freezing and thawing issues, can incorporate into acondensed aerosol fire suppression system, can be used in powder fireextinguishers, etc.); and (4) the advantage of new flame retardantpowder with no flame retardant additives that are hygroscopic (e.g.,ammonia sulphate)—longer shelf life, higher ease of handling, etc.).

Further objects, features and advantages of the present disclosure willbe understood by reference to the following drawings and detaileddescription.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the development of a fire carried out in 3 phases.

FIG. 2 shows the combustion process.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The development of a fire is carried out in 3 phases, namely, (1)initiating fire, (2) fully developed fire, and (3) the decreasing fire,as shown in FIG. 1.

A flame retardant suppresses or stops the combustion process. Dependingon their chemical nature (or composition), flame retardants can actchemically and/or physically in the solid, liquid or gas phases, asshown in FIG. 2.

The fire retardant compositions of this disclosure are substances thatreduce the flammability or delay the combustion of another material,typically referred to as a fuel. This effect can be accomplished throughphysical and/or chemical mechanisms. These two general classificationsof flame retardant mechanisms can by further broken down as physicaldilution, chemical interaction, inert gas dilution, thermal quenching,and the formation of protective coatings. Each of these mechanisms isfunctionally different, but can be combined in the same flame retardant.

The physical dilution mechanism operates by the flame retardantfunctioning as a thermal sink. This typically increases the heatcapacity of the product, allowing it to remain at a lower temperature,preventing ignition.

With physical dilution, the flame retardant additives such as the watersoluble ammonium polyphosphate (APP), ammonium dihydrogen phosphate(MAP), and di-ammonium hydrogen phosphate (DAP), upon decomposition, canrelease inert gases to dilute the fuel in the solid and gaseous phases,and thereby lowering the ignition limit of the combined gas mixture.

Chemical interaction is a mechanism that functions through thegeneration of free radical species. These species are generated at theflame retardant is consumed, as a product of thermal degradation. Thesefree radicals compete and interfere with the combustion process byreacting in place of oxygen. In addition, in the presence of polymers,these materials can increase the amount of char produced.

With chemical interaction in the gas phase, the free radical mechanismof the combustion process, which takes place in the gas phase, isinterrupted by the flame retardant (e.g., halogenated flame retardantssuch as ammonium bromide). The exothermic processes contributed by thefree radicals are thus stopped. Consequently, the supply of new feedingflammable gases reduces, leading to the cooling of the system andeventually, complete flame suppression.

With chemical interaction in the solid phase, the flame retardant, suchas the water soluble ammonium polyphosphate (APP), ammonium dihydrogenphosphate (MAP), and di-ammonium hydrogen phosphate (DAP), can cause alayer of carbon to form on the exposed surface of the burning substrate.This can happen, for example, through the dehydrating action of theflame retardant generating double carbon bonds inside the substrate.This leads to the formation of the carbonaceous layer via acidizing andcrosslinking.

Inert gas dilution as a mechanism is in some way similar to chemicalinteraction. Instead of producing free radicals to compete withcombustion in place of oxygen, inert gas dilution seeks to disruptcombustion by displacing oxygen. This is accomplished by producing largeamount of non-flammable gas during thermal decomposition.

Thermal quenching operates through endothermic degradation of the flameretardant. This effectively cools the product and retards the pyrolysisprocess.

With thermal quenching, endothermic processes triggered by additives,such as the water soluble ammonium polyphosphate (APP), ammoniumdihydrogen phosphate (MAP), and di-ammonium hydrogen phosphate (DAP),cool the substrate to a temperature below that required to sustain thecombustion process.

The formation of a protective coating is another method by which fireretardation is possible. During decomposition of the flame retardant, abarrier of liquid material or char is formed, insulting the product toreduce heat transfer. The best example of this mechanism is intumescentsystems, which form thick layers of flame resistant foam around aparticular product. In addition, phosphate compounds are commonly used.During combustion, many containing compounds decompose to formphosphoric acid. This phosphoric acid in turn polymerizes, creating aglassy layer insulting the product.

With formation of a protective layer or coating, the condensedcombustible layer is shielded from the gaseous phase with a solid orgaseous protective layer. Owing to the shielding effects of theprotective layer, the heat exchange (or transfer) between the hotgaseous phase and the condensed combustible layer is impeded. With that,the condensed phase underneath gets time to cool down. Smaller amount ofpyrolysis gases also get evolved into the gaseous phase. In addition,there is hindered access of the surrounding (or atmospheric) oxygen toreach the condensed combustible layer to continue the combustion.Examples include phosphorus and boron compounds.

In an embodiment, the flame retardant compositions of this disclosureoperate through a combination of mechanisms. Each component of a flameretardant formulation may be individually ineffective, but can have asynergistic effect when combined. The flame retardant compositions ofthis disclosure operate through a combination of several mechanismsincluding, for example, chemical interaction, thermal quenching, inertgas dilution, and protective coating.

In an embodiment, this disclosure is directed to a compositioncomprising one or more substrate materials and a flame retardant powdercomposition. The flame retardant powder composition comprises at leastone flame retardant salt, and a nitrogen-containing compound.

In another embodiment, this disclosure is directed to a flame retardantcomposition comprising at least one flame retardant salt, anitrogen-containing compound, and water.

In an embodiment, this disclosure is directed to a compositioncomprising one or more substrate materials and a flame retardantcomposition. The flame retardant composition comprises from about 10 toabout 90 weight percent of at least one flame retardant salt, from about10 to about 60 weight percent of a nitrogen-containing compound, andoptionally from about 1 to about 95 weight percent of water; wherein theentirety of the components is 100 weight percent. The at least one flameretardant salt comprises water soluble ammonium polyphosphate (APP), andthe nitrogen-containing compound comprises urea.

In an embodiment, this disclosure is directed to a one or more substratematerials and a flame retardant composition. The flame retardantcomposition comprises from about 10 to about 90 weight percent of atleast one flame retardant salt, from about 10 to about 60 weight percentof a nitrogen-containing compound, and optionally from about 1 to about95 weight percent of water; wherein the entirety of the components is100 weight percent. The at least one flame retardant salt compriseswater soluble ammonium polyphosphate (APP), ammonium dihydrogenphosphate (MAP), and di-ammonium hydrogen phosphate (DAP); and thenitrogen-containing compound comprises urea.

In an embodiment, this disclosure further is directed to a compositioncomprising one or more substrate materials and a flame retardantcomposition. The flame retardant composition comprises from about 10 toabout 90 weight percent of at least one flame retardant salt, from about10 to about 60 weight percent of a nitrogen-containing compound, andoptionally from about 1 to about 95 weight percent of water; wherein theentirety of the components is 100 weight percent. The at least one flameretardant salt comprises water soluble ammonium polyphosphate (APP) andammonium bromide; and the nitrogen-containing compound comprises urea.

For phosphorus-containing flame retardants, the generic mode of actionis the formation of a solid charred surface layer of phosphoruscompounds and, in specific cases, the interruption of the radical chainprocess in the gas phase. While halogen containing flame retardants actin the gas phase, phosphorous-containing flame retardants primarilyinfluence the reactions taking place in the condensed phase.

The phosphorus-containing flame retardant is transformed into phosphoricacid by thermal degradation, and water is released from the substrate inthe solid phase as shown below.

The phosphoric acid forms a protective layer through (a) esterification,and (b) dehydration of the oxygen-containing substrate (i.e., charring).The protective layer consists of interpenetrating networks of carbon andphosphorous oxides as shown below.(HPO₃)_(n)+C_(x)(H₂O)_(m)→[“C”]_(x)+(HPO₃)_(n) ×mH₂O

Specific phosphorus flame retardants, such as the metal phosphinates,may also act in the gas phase by the formation of P and PO radicals,which interrupt the radical chain mechanism of the combustion process.

Illustrative phosphorus-containing flame retardants include, forexample, resorcinol bis (diphenyl phosphate) (RDP), triaryl phosphates,metal phosphinates, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide(DOPO) and its derivatives, trischloropropyl phosphate (TCCP), ammoniumpolyphosphate (APP), red phosphorous, and the like.

Preferred phosphorus-containing flame retardants of this disclosureinclude, for example, water soluble ammonium polyphosphate (APP),ammonium dihydrogen phosphate (MAP), and di-ammonium hydrogen phosphate(DAP).

Illustrative di-ammonium hydrogen phosphate (DAP) chemical reactionsinclude, for example, the following:(NH₄)₂HPO₄(s)═NH₃(g)+NH₄H₂PO₄(s)  (1)NH₄H₂PO₄(s)═N_(H)(g)+H₃PO₄(l)  (2)2H₃PO₄(l)═P₂O₅(s)+3H₂O(l)  (3)

Illustrative ammonium dihydrogen phosphate (MAP) chemical reactionsinclude, for example, the following:NH₄H₂PO₄(s)═NH₃(g)+H₃PO₄(l)  (2)2H₃PO₄(l)═P₂O₅(s)+3H₂O(l)  (3)

Illustrative water soluble ammonium polyphosphate (APP) chemicalreactions include, for example, the following:(NH₄PO₃)_(n)→NH₃(g)+H₃PO₄(l)  (2)

With regard to the above chemical reactions, the evolution of waterabsorbs heat, and thereby reduces the transport processes of heatconduction and lowers the flame temperature. H₃PO₄ (the phosphorusoxo-acids containing P in oxidation state+5) is a very viscous liquid,which acts as a film on the cellulose fibers, thereby damming andblocking up the issuing pyrolysate. The phosphorus oxo-acid acts as anacid catalyst in the dehydration of carbon-based polyalcohols, such ascellulose in wood. This forms a charred layer over the substrate. Thecarbonaceous char helps to shield the underlying condensed layer fromfurther attacks by oxygen and radiant heat. The phosphorus oxo-acidreacts with alcohol groups to form heat-unstable phosphate esters. Theesters subsequently decompose to release carbon dioxide (CO₂), andregenerate the phosphoric acid catalyst. In the gas phase, the releaseof non-flammable carbon dioxide (CO₂) helps to dilute the oxygen of theair and flammable decomposition products of the material that isburning. The solid P₂O₅ has the ability of directing cellulosecombustion to produce carbon monoxide instead of carbon dioxide as shownbelow.5C+P₂O₅=5CO+2P  (4)In regard to equation (4), the exothermic reactivity of the systemreduces, and this cooling effect hence can be deemed as a fireextinguishing step.

Preferred ammonium salts of phosphoric acid include, for example,mono-ammonium phosphate, diammonium phosphate, ammonium polyphosphate,and the like. The ammonium salt of phosphoric acid can be present in theflame retardant powder composition in an amount from about 10 to about90 weight percent, preferably from about 15 to about 80 weight percent,and more preferably from about 20 to about 70 weight percent, based onthe total weight of the flame retardant powder composition.

Water soluble ammonium polyphosphate is an essential ingredient in theflame retardant compositions of this disclosure. The water solubleammonium polyphosphate has a total nitrogen as N from about 5 to about15 weight percent, and a total phosphorus as P₂O₅ from about 30 to about40 weight percent, based on the total weight of the ammoniumpolyphosphate. The water soluble ammonium polyphosphate has a densityfrom about 1.75 to about 1.90 g/cm³, a water solubility of greater thanabout 60 g/100 ml, and a pH from about 6.5 to about 8.5.

For bromine-containing and chlorine-containing flame retardants, thegeneric mode of action is the interruption of the radical chainmechanism of the combustion process in the gas phase. High-energy OH*and H* radicals are formed by chain-branching in the fire as follows:

The high-energy OH* and H* radicals formed by chain-branching in thefire are removed by the halogen-containing flame retardant as follows:

1. Release of Halogen Radicals (X*═CI*, or Sr*) from the Flame Retardant(R—X).R—X→R*+X*

2. Formation of Hydrogen Halides (HX).HX+H*→H₂+X*HX+OH*→H₂O+X*

3. Neutralization of Energy-Rich Radicals.HX+H*→H₂+X*HX+OH*→H₂O+X*

The high-energy H* and OH* radicals are removed from the gas phase byreaction with HX and replaced with low-energy X* radicals. The actualflame effect is thus produced by HX. The hydrogen halide consumed isregenerated by reaction with hydrocarbon as shown below. Thus, HXultimately acts as a catalyst.X*+RH→R*+HX

Illustrative bromine-containing and chlorine-containing flame retardantsinclude, for example, tetrabromobisphenol A (TBBA) and its derivatives,tetrabromobisphenol acid, decabromdiphenyl ether (deca-BDE),hexabromcyclododecane (HBCDD), chloroparaffins,dedecachloropentacyclooctadecadiene (dechlorane), and the like.

Upon heating, ammonium bromide decomposes into ammonia gas and liquidhydrogen bromide. Illustrative ammonium bromide chemical reactionsinclude, for example, the following:NH₄Br(s)═NH₃(g)+HBr(l)HBr(l)→HBr(g)

Preferred ammonium salts of hydrobromic acid include, for example,ammonium bromide, ammonium chloride, magnesium chloride, and the like.The ammonium salt of hydrobromic acid can be present in the flameretardant powder composition in an amount from about 10 to about 50weight percent, preferably from about 15 to about 45 weight percent, andmore preferably from about 20 to about 40 weight percent, based on thetotal weight of the flame retardant powder composition.

For nitrogen-containing compounds, the generic mode of action is therelease of inert gases (e.g., ammonia and nitrogen) into the gas phaseor by condensation reactions in the solid phase.

Illustrative nitrogen-containing compound chemical reactions include,for example, the following:(NH₂)₂CO(s)+H₂O(l)→NH₃(g)+H₂CO₃(l)H₂CO₃(l)→H₂O(g)+CO₂(g)

Urea releases non-combustible gases such as ammonia (NH₃), water vapor(H₂O) and carbon dioxide (CO₂) that dilute combustible gases and lowersthe flame temperature in the gas phase. Urea can work in synergy withalum and potassium bicarbonate salts.

Illustrative nitrogen-containing compounds include, for example,guanidine (present in urea), melamine, melamine cyanurate (MC), melaminepolyphosphate (MPP)+metal phosphinates (synergy), melamine poly(zinc- oraluminum)phosphates+metal phosphinates (synergy), melamine-based HALS(Hindered Amine Light Stabilizer), and the like.

The preferred nitrogen-containing compound is urea.

The nitrogen-containing compounds (i.e., urea) can be present in theflame retardant powder composition in an amount from about 10 to about60 weight percent, preferably from about 12 to about 55 weight percent,and more preferably from about 15 to about 50 weight percent, based onthe total weight of the flame retardant powder composition.

Illustrative ammonium salts of sulfuric acid include, for example,ammonium sulfate, and the like. The ammonium salt of sulfuric acid canbe present in the flame retardant powder composition in an amount fromabout 10 to about 20 weight percent, preferably from about 11 to about19 weight percent, and more preferably from about 12 to about 18 weightpercent, based on the total weight of the flame retardant powdercomposition.

Illustrative ammonium salts of hydrochloric acid include, for example,ammonium chloride, and the like. The ammonium salt of hydrochloric acidcan be present in the flame retardant powder composition in an amountfrom about 10 to about 20 weight percent, preferably from about 11 toabout 19 weight percent, and more preferably from about 12 to about 18weight percent, based on the total weight of the flame retardant powdercomposition.

Other additives can be present in the flame retardant powder compositionin an amount from about 0.1 to about 30 weight percent, preferably fromabout 0.5 to about 25 weight percent, and more preferably from about 1to about 20 weight percent, based on the total weight of the flameretardant powder composition.

Illustrative of such other additives include, for example, alum(hydrated potassium aluminum sulfate), sodium stannate, sodium orpotassium silicate (liquid glass), sodium borate (borax), carboxymethylcellulose, starch-like compounds (e.g., cassava liquid, sweet potato,tapioca extract, or catalase), organophosphorus nitrogen compounds,glycerin or glycerol, isocyanates, polyurethanes, organosilicones,pentaerythitol, 4A natural zeolite, surfactants (e.g., anionic,cationic, nonionic, and zwitterionic), solvents (e.g., organic solventssuch as aromatic compounds, alcohols, esters, ethers, ketones, amines,nitrated hydrocarbons, and halogenated hydrocarbons), and the like.

Carboxymethyl cellulose (CMC) is a cellulose derivative withcarboxymethyl groups (—CH₂—COOH) bound to some of the hydroxyl groups ofthe glucopyranose monomers that make up the cellulose backbone. Theaddition of CMC to flame retardant compositions of this disclosureincreases the viscosity of the prepared flame retardant solution. Thehigher viscosity aids in the pick-up of the flame retardant solutionduring the padding process. In addition, CMC also acts as acarbonization agent. For every 80 ml of water introduced to prepare theflame retardant solution, add 1-2 ml teaspoon of CMC powder. If a flameretardant solution of higher viscosity is needed, more CMC powder can beadded in a later time. The setback of having too much CMC powder is thelonger time needed for treated samples to dry under room temperatureconditions. Other alternatives to CMC powder are glycerin, PEG(polyethylene glycol) 400 and PVA (polyvinyl alcohol), and the like.

Borax (also known as sodium borate, sodium tetraborate, or disodiumtetraborate) is an important boron compound, a mineral, and a salt ofboric acid. Powdered borax is white, consisting of soft colorlesscrystals that dissolve in water. In accordance with this' disclosure,the decahydrate version of borax, i.e., Na₂B₄O₇.10H₂O, is preferred.Borax is a flame retardant additive. In accordance with this disclosure,5-20 wt % of borax can be added into the flame retardant compositionbefore making a flame retardant solution. If 20 wt % of borax is used,water needs to be heated (about 60° C.-90° C.) to facilitate thedissolution of borax crystals. Borax imparts the added benefit ofslowing the spread of surface flames if burning occurs. This isattributed to char-formation, low melting point and glassy filmformation, which help to block volatile compounds from reaching theflames. Borax is low cost and has minimal impact on the substrate'sphysical properties. In addition, borax releases water in highquantities which cools down combustion temperature and evolution ofwater vapor that dilutes combustible gases. Other benefits of boraxinclude, for example, it acts as an anti-corrosive protecting metals incellulosic materials; suppresses glowing, smoldering and smoke; andplays synergistic value with other fire retardants.

Sodium (or potassium) silicate is also known as liquid glass—Na₂(SiO₂)_(n)O or Na₂SiO₃.nH₂O. In accordance with this disclosure, thenono hydrate version, i.e., Na₂SiO₃.9H₂O, is preferred. Sodium silicateis a flame retardant additive that is soluble in water. In accordancewith this disclosure, 5-20 wt % of sodium silicate can be added into theflame retardant composition before making a flame retardant solution. If20 wt % of sodium silicate is used, water needs to be heated (about 60°C.-90° C.) to facilitate the dissolution of silicate crystals. Uponcombustion, sodium silicate forms a glassy layer that insulates andprevents oxygen from reaching the substrate. Sodium silicates areinherently intumescent. Treated samples should be waterproofed to ensurelong-term passive fire protection (PFP). When sodium silicates areadequately protected, they function extremely well and reliably for longperiods. Sodium silicate, both in bead form and in liquid form, areinherently endothermic, due to the liquid water in the water glass thatundergoes hydrolysis. Potassium silicate functions in a similar way tosodium silicate.

Glycerin (or glycerol, C₃H₈O₃), is a simple polyol compound. It is acolorless, odorless, viscous liquid that is sweet-tasting and non-toxic.Glycerol has three hydroxyl groups that are responsible for itssolubility in water. In accordance with this disclosure, 10-20 wt % ofglycerin can be added during the preparation of the flame retardantsolution that contains borax and sodium silicate. Glycerin promotes thedissolution of borax and sodium silicate in water at room temperature.If the flame retardant solution does not contain borax and/or sodiumsilicate, 0.5-1.0 wt % glycerin can also be added to suppress glowing,smoldering and smoke when burning occurs.

Isocyanates, which are organic compounds containing the functional groupwith the formula R—N═C═O, are useful additives. Isocyanates areelectrophiles, and as such they are reactive toward a variety ofnucleophiles including alcohols, amines, and even water. Upon treatmentwith an alcohol (e.g., glycerin, PEG 400, PVA and PER), an isocyanateforms a urethane linkage (shown below):ROH+R′NCO→ROC(O)N(H)R′(R and R′ are alkyl or aryl groups)

An isocyanate that has two isocyanate groups is known as adi-isocyanate. If a di-isocyanate is treated with a compound containingtwo or more hydroxyl groups, such as a diol or a polyol (e.g., glycerin,PEG 400, PVA and PER), polymer chains are formed, which are known aspolyurethanes. Isocyanates also react with water to form carbon dioxide(shown below):RNCO+H₂O→RNH₂+CO₂

The polyurethanes crosslink and bind the water-soluble flame retardantcomposition to the substrate, thereby making the flame retardantcomposition stay intact after laundering. The recommended amount ofisocyanates to be added will be in the range of 10-30% of the flameretardant composition powder wt %.

Organosilicones (e.g., n-octyltriethoxysilane, C₁₄H₃₂O₃Si), are used tointroduce water-proof protection to the flame retardant compositioncoat. Another alternative is potassium methyl siliconate (e.g.,CH₃K₃O₃Si). Basically, a crosslinking reaction happens between the Si—OHin the flame retardant coating and the Si—OH in the organosiliconesand/or potassium methyl siliconate under hydrolysis. The end resultleads to the formation of an excellent water-proof layer. Therecommended amount of organosilicones and/or potassium methyl siliconateto be added will be in the range of 0.5-1.0 wt % of the flame retardantsolution.

Pentaerythitol (PER, C₅H₁₂O₄), is an organic compound, a white,crystalline solid. It is a polyol, with the neopentane backbone and onehydroxyl group in each of the four terminal carbons. It is a buildingblock for the synthesis and production of explosives, plastics,appliances, and many other important chemicals. It can serve as acarbonization agent. The recommended dosage is 1.0-4.0 wt % of the flameretardant powder.

A natural zeolite is a halogen-free intumescent flame retardantadditive. Another substitute is apatite. The recommended dosage is1.0-60 wt % of the flame retardant powder.

The surfactant can be an anionic, cationic, nonionic, or zwitterionicsurfactant. The surfactant may act as a detergent, wetting agent,emulsifier, foaming agent, dispersant, adsorbent, and the like.Illustrative surfactants useful in the compositions of this disclosureinclude, for example, polyalkylene glycols, and the like. Therecommended amount of surfactant to be added will be in the range of0.5-5.0 wt % of the flame retardant solution.

The solvent can be any solvent suitable for use in the compositions ofthis disclosure. Illustrative solvents include, for example, organicsolvents such as an aromatic compound, alcohol, ester, ether, ketone,amine, nitrated hydrocarbon, halogenated hydrocarbon, and the like. Therecommended amount of solvent to be added will be in the range of 1-10wt % of the flame retardant solution.

The substrate material can be present in an amount from about 5 weightpercent to about 95 weight percent, preferably from about 10 to about 90weight percent, and more preferably form about 25 to about 75 weightpercent, based on the total weight of the substrate material/flameretardant composition. The flame retardant composition is present in anamount from about 5 weight percent to about 95 weight percent,preferably from about 10 to about 90 weight percent, and more preferablyform about 25 to about 75 weight percent, based on the total weight ofthe substrate material/flame retardant composition.

In an embodiment, this disclosure is directed to a process for preparinga flame retardant powder composition. The process comprises adding to acontainer at least one flame retardant salt and a nitrogen-containingcompound, and mixing the contents of the container to give a dispersedmixture comprising the flame retardant powder composition.

Processing conditions for the preparation of the flame retardant powdercompositions of this disclosure, such as temperature, pressure and mixtime, may also vary greatly and any suitable combination of suchconditions may be employed herein. Normally the process is carried outunder ambient temperature, ambient pressure and the mix time may varyfrom a matter of seconds or minutes to a few hours or greater. Theingredients can be added to the mixture or combined in any order. Themix time employed can range from about 0.1 to about 10 hours, preferablyfrom about 0.25 to 8 hours, and more preferably from about 0.5 to 4hours, for all steps.

In an embodiment, this disclosure is also directed to a compositioncomprising one or more substrate materials and a flame retardantcomposition. The flame retardant composition comprises at least oneflame retardant salt, a nitrogen-containing compound, and water.

In an embodiment, this disclosure is directed to a process for preparinga flame retardant water based composition. The process comprises addingto a container at least one flame retardant salt, a nitrogen-containingcompound, and water; and mixing the contents of the container to give adissolved solution comprising the flame retardant water basedcomposition.

Processing conditions for the preparation of the flame retardant waterbased compositions of this disclosure, such as temperature, pressure andmix time, may also vary greatly and any suitable combination of suchconditions may be employed herein. Normally the process is carried outunder ambient temperature, ambient pressure and the mix time may varyfrom a matter of seconds or minutes to a few hours or greater. Theingredients can be added to the mixture or combined in any order. Themix time employed can range from about 0.1 to about 10 hours, preferablyfrom about 0.25 to 8 hours, and more preferably from about 0.5 to 4hours, for all steps.

In accordance with this disclosure, an intumescent process is providedfor forming an insulating protective layer on a substrate. The processcomprises: (a) providing a flame retardant composition comprising atleast one flame retardant salt, a nitrogen-containing compound, andoptionally water, in which the at least one flame retardant saltcomprises an ammonium salt of phosphoric acid, and thenitrogen-containing compound comprises urea; (b) heating the ammoniumsalt of phosphoric acid to give an inorganic acid; (c) carbonizing theinorganic acid with a polyalcohol present in the substrate; (d)hydrolyzing urea to give ammonia and reacting ammonia to give nitrogengas; (e) foaming the mixture of the carbonized inorganic acid and thenitrogen gas; and (f) solidifying the foam through one or more crosslinking reactions to form the insulating protective layer on thesubstrate.

Intumescence is the formation of a voluminous insulating protectivelayer through carbonization and simultaneous foaming. Intumescent FRsystems ‘puff up’ to produce foams They are used to protect combustiblematerials such as plastics or wood, and those like steel, which losetheir strength when exposed to high temperatures, against the attack ofheat and fire.

Basically, intumescent flame retardant systems consist of the followingthree things: (i) “carbon” donors (e.g., polyalcohols which are presentin cotton, wood and paper), (ii) acid donors (e.g., ammoniumpolyphosphate), and (iii) gas producing compounds (e.g., urea, APP,P₂O₅).

In particular, the intumescent process mechanism includes the following:

1. Release of an Inorganic Acid (e.g., Ammonium Polyphosphate or APP)

2. Carbonization (e.g., of Polyalcohols)(HPO₃)_(n)+C_(x)(H₂O)_(m)→[“C”]_(x)+(HPO₃)_(n) ×mH₂O

3. Gas Formation

4. Foaming of the Mixture

5. Solidification Through Crosslinking Reactions

In an embodiment, this disclosure provides a process for the productionof an extruded article. The process comprises heating a polymer to forma polymer melt, adding a flame retardant powder composition to thepolymer melt to form a flame retardant polymer melt, and extruding theflame retardant polymer melt to give an extruded article. The flameretardant composition comprises at least one flame retardant salt and anitrogen-containing compound.

Illustrative flame retardant powder compositions are described herein.Illustrative polymers include, for example, thermoplastic polymers andthermosets.

Illustrative thermoplastic polymers include, for example, the following:

(1) Polymers of monoolefins and diolefins, for example, polypropylene,polyisobutylene, poly-but-1-ene, poly-4-methylpent-1-ene,polyvinylcyclohexane, polyisoprene or polybutadiene, as well as polymersof cycloolefins, for instance of cyclopentene or norbornene,polyethylene (which optionally can be cross linked), for example, highdensity polymethylene (HDPE), high density and high molecular weightpolyethylene (HDPE-HMW), high density and ultrahigh molecular weightpolyethylene (HDPE-UHMW), medium density polyethylene (MDPE), lowdensity polyethylene (LDPE), linear low density polyethylene (LLDPE),(VLDPE) and (ULDPE). Polyolefins, i.e., the polymers of monoolefinsexemplified in the preceding paragraph, preferably polyethylene andpolypropylene, can be prepared by different and especially by thefollowing methods:

(a) Radical polymerization (normally under high pressure and at elevatedtemperature).

(b) Catalytic polymerization using a catalyst that normally contains oneor more than one metal of groups IVb, Vb, VIb or VIII of the PeriodicTable. These metals usually have one or more than one ligand, typicallyoxides, halides, alcoholates, esters, ethers, amines, alkyls, alkenylsand/or aryls that may be either π- or σ-bond coordinated. These metalcomplexes may be in the free form or fixed on substrates, typically onactivated magnesium chloride, titanium (III) chloride, alumina orsilicon oxide. These catalysts may be soluble or insoluble in thepolymerization medium. The catalysts can be used by themselves in thepolymerization or further activators may be used, typically metalalkyls, metal hydrides, metal alkyl halides, metal alkyl oxides or metalalkyloxanes, said metals being elements of groups Ia, IIa and/or IIIa ofthe Periodic Table. The activators may be modified conveniently withfurther ester, ether, and amine or silyl ether groups.

(2) Mixtures of the polymers mentioned under (1), for example, mixturesof polypropylene with polyisobutylene, polypropylene with polyethylene(for example, PP/HDPE, PP/LDPE) and mixtures of different types ofpolyethylene (for example, LDPE/HDPE).

(3) Copolymers of monoolefins and diolefins with each other or withother vinyl monomers, for example ethylene/propylene copolymers, linearlow density polyethylene (LLDPE) and mixtures thereof with low densitypolyethylene (LDPE), propylene/but-1-ene copolymers,propylene/isobutylene copolymers, ethylene/but-1-ene copolymers,ethylene/hexene copolymers, ethylene/methylpentene copolymers,ethylene/heptene copolymers, ethylene/octene copolymers,ethylene/vinylcyclohexane copolymers, ethylene/cycloolefin copolymers(e.g., ethylene/norbornene like COC), ethylene/1-olefins copolymers,where the 1-olefin is generated in-situ; propylene/butadiene copolymers,isobutylene/isoprene copolymers, ethyl ene/vinylcyclohexene copolymers,ethylene/alkyl acrylate copolymers, ethylene/alkyl methacrylatecopolymers, ethylene/vinyl acetate copolymers or ethylene/acrylic acidcopolymers and their salts (ionomers) as well as terpolymers of ethylenewith propylene and a diene such as hexadiene, dicyclopentadiene orethylidene-norbornene; and mixtures of such copolymers with one anotherand with polymers mentioned in (1) above, for examplepolypropylene/ethylene-propylene copolymers, LDPE/-ethylene-vinylacetate copolymers (EVA), LDPE/ethylene-acrylic acid copolymers (EAA),LLDPE/EVA, LLDPE/EAA and alternating or random polyalkylene/carbonmonoxide copolymers and mixtures thereof with other polymers, forexample polyamides.

(4) Hydrocarbon resins (for example C₅-C₉) including hydrogenatedmodifications thereof (e.g., tackifiers) and mixtures of polyalkylenesand starch. The homopolymers and copolymers mentioned above may have astereo structure including syndiotactic, isotactic, hemi-isotactic oratactic; where atactic polymers are preferred. Stereo block polymers arealso included.

(5) Polystyrene, poly(p-methyl styrene), poly(α-methylstyrene).

(6) Aromatic homopolymers and copolymers derived from vinyl aromaticmonomers including styrene, .alpha.-methylstyrene, all isomers of vinyltoluene, especially p-vinyl toluene, all isomers of ethyl styrene,propyl styrene, vinyl biphenyl, vinyl naphthalene, and vinyl anthracene,and mixtures thereof. Homopolymers and copolymers may have a stereostructure including syndiotactic, isotactic, hemi-isotactic or atactic;where atactic polymers are preferred. Stereo block polymers are alsoincluded;

(a) Copolymers including aforementioned vinyl aromatic monomers andcomonomers selected from ethylene, propylene, dienes, nitriles, acids,maleic anhydrides, maleimides, vinyl acetate and vinyl chloride oracrylic derivatives and mixtures thereof, for example styrene/butadiene,styrene/acrylonitrile, styrene/ethylene (interpolymers), styrene/alkylmethacrylate, styrene/butadiene/alkyl acrylate, styrene/butadiene/alkylmethacrylate, styrene/maleic anhydride, styrene/acrylonitrile/methylacrylate; mixtures of high impact strength of styrene copolymers andanother polymer, for example a polyacrylate, a diene polymer or anethylene/propylene/diene terpolymer; and block copolymers of styrenesuch as styrene/butadiene/styrene, styrene/isoprene/styrene,styrene/ethylene/butylene/styrene or styrene/ethylene/propylene/styrene.

(b) Hydrogenated aromatic polymers derived from hydrogenation ofpolymers mentioned under (6), especially includingpolycyclohexylethylene (PCHE) prepared by hydrogenating atacticpolystyrene, often referred to as polyvinylcyclohexane (PVCH).

(c) Hydrogenated aromatic polymers derived from hydrogenation ofpolymers mentioned under (6a). Homopolymers and copolymers may have astereo structure including syndiotactic, isotactic, hemi-isotactic oratactic; where atactic polymers are preferred. Stereo block polymers arealso included.

(7) Graft copolymers of vinyl aromatic monomers such as styrene or.alpha.-methylstyrene, for example, styrene on polybutadiene, styrene onpolybutadiene-styrene or polybutadiene-acrylonitrile copolymers; styreneand acrylonitrile (or methacrylonitrile) on polybutadiene; styrene,acrylonitrile and methyl methacrylate on polybutadiene; styrene andmaleic anhydride on polybutadiene; styrene, acrylonitrile and maleicanhydride or maleimide on polybutadiene; styrene and maleimide onpolybutadiene; styrene and alkyl acrylates or methacrylates onpolybutadiene; styrene and acrylonitrile on ethylene/propylene/dieneterpolymers; styrene and acrylonitrile on polyalkyl acrylates orpolyalkyl methacrylates, styrene and acrylonitrile on acrylate/butadienecopolymers, as well as mixtures thereof with the copolymers listed under(6), for example the copolymer mixtures known as ABS, MBS, ASA or AESpolymers.

(8) Halogen-containing polymers such as polychloroprene, chlorinatedrubbers, chlorinated and brominated copolymer of isobutylene-isoprene(halobutyl rubber), chlorinated or sulphochlorinated polyethylene,copolymers of ethylene and chlorinated ethylene, epichlorohydrin homo-and copolymers, especially polymers of halogen-containing vinylcompounds, for example polyvinyl chloride, polyvinylidene chloride,polyvinyl fluoride, polyvinylidene fluoride, as well as copolymersthereof such as vinyl chloride/vinylidene chloride, vinyl chloride/vinylacetate or vinylidene chloride/vinyl acetate copolymers.

(9) Polymers derived from α, β-unsaturated acids and derivatives thereofsuch as polyacrylates and polymethacrylates; polymethyl methacrylates,polyacrylamides and polyacrylonitriles, impact-modified with butylacrylate.

(10) Copolymers of the monomers mentioned under (9) with each other orwith other unsaturated monomers, for example, acrylonitrile/butadienecopolymers, acrylonitrile/alkyl acrylate copolymers,acrylonitrile/alkoxyalkyl acrylate or acrylonitrile/vinyl halidecopolymers or acrylonitrile/alkyl methacrylate/butadiene terpolymers.

(11) Polymers derived from unsaturated alcohols and amines or the acylderivatives or acetals thereof, for example polyvinyl alcohol, polyvinylacetate, polyvinyl stearate, polyvinyl benzoate, polyvinyl maleate,polyvinyl butyral, polyallyl phthalate or polyallyl melamine; as well astheir copolymers with olefins mentioned in 1 above.

(12) Homopolymers and copolymers of cyclic ethers such as polyalkyleneglycols, polyethylene oxide, polypropylene oxide or copolymers thereofwith bisglycidyl ethers.

(13) Polyacetals such as polyoxymethylene and those polyoxymethylenes,which contain ethylene oxide as a co-monomer; polyacetals modified withthermoplastic polyurethanes, acrylates or MBS.

(14) Polyphenylene oxides and sulphides, and mixtures of polyphenyleneoxides with styrene polymers or polyamides.

(15) Polyurethanes derived from hydroxyl-terminated polyethers,polyesters or polybutadienes on the one hand and aliphatic or aromaticpolyisocyanates on the other, as well as precursors thereof.

(16) Polyamides and co-polyamides derived from diamines and dicarboxylicacids and/or from aminocarboxylic acids or the corresponding lactams,for example polyamide 4, polyamide 6, polyamide 6/6, 6/10, 6/9, 6/12,4/6, 12/12, polyamide 11, polyamide 12, aromatic polyamides startingfrom m-xylene diamine and adipic acid; polyamides prepared fromhexamethylenediamine and isophthalic or/and terephthalic acid and withor without an elastomer as modifier, for examplepoly-2,4,4-trimethylhexamethylene terephthalamide or poly-m-phenyleneisophthalamide; and also block copolymers of the aforementionedpolyamides with polyolefins, olefin copolymers, ionomers or chemicallybonded or grafted elastomers; or with polyethers, e.g. with polyethyleneglycol, polypropylene glycol or polytetramethylene glycol; as well aspolyamides or co-polyamides modified with EPDM or ABS; and polyamidescondensed during processing (RIM polyamide systems).

(17) Polyureas, polyimides, polyamide imides, polyether imides,polyester imides, polyhydantoins and polybenzimidazoles.

(18) Polyesters derived from dicarboxylic acids and diols and/or fromhydroxycarboxylic acids or the corresponding lactones, for examplepolyethylene terephthalate, polybutylene terephthalate,poly-1,4-dimethylolcyclohexane terephthalate, polyalkylene naphthalate(PAN) and polyhydroxybenzoates, as well as block co-polyether estersderived from hydroxyl-terminated polyethers; and also polyestersmodified with polycarbonates or MBS.

(19) Polyketones.

(20) Polysulphones, polyether sulphones and polyether ketones.

(21) Blends of the aforementioned polymers (polyblends), for example,PP/EPDM, Polyamide/EPDM or ABS, PVC/EVA, PVC/ABS, PVC/MBS, PC/ABS,PBTP/ABS, PC/ASA, PC/PBT, PVC/CPE, PVC/acrylates, POM/thermoplastic PUR,PC/thermoplastic PUR, POM/acrylate, POM/MBS, PPO/HIPS, PPO/PA 6.6 andcopolymers, PA/HDPE, PA/PP, PA/PPO, PBT/PC/ABS or PBT/PET/PC.

(22) Polycarbonates, for example, that are obtainable by interfacialprocesses or by melt processes (catalytic transesterification). Thepolycarbonate may be either branched or linear in structure and mayinclude any functional substituents. Polycarbonate copolymers andpolycarbonate blends are also within the scope of this disclosure. Theterm polycarbonate should be interpreted as inclusive of copolymers andblends with other thermoplastics. Methods for the manufacture ofpolycarbonates are known, for example, from U.S. Pat. Nos. 3,030,331;3,169,121; 4,130,458; 4,263,201; 4,286,083; 4,552,704; 5,210,268; and5,606,007. A combination of two or more polycarbonates of differentmolecular weights may be used. Preferred are polycarbonates obtainableby reaction of a diphenol, such as bisphenol A, with a carbonate source.The carbonate source may be a carbonyl halide, a carbonate ester or ahaloformate. Suitable carbonate halides are phosgene or carbonylbromide.Suitable carbonate esters are dialkylcarbonates, such as dimethyl- ordiethylcarbonate, diphenyl carbonate, phenyl-alkylphenylcarbonate, suchas phenyl-tolylcarbonate, dialkylcarbonates, such as dimethyl- ordiethylcarbonate, di-(halophenyl)carbonates, such asdi-(chlorophenyl)carbonate, di-(bromophenyl)carbonate,di-(trichlorophenyl)carbonate or di-(trichlorophenyl)carbonate,di-(alkylphenyl)carbonates, such as di-tolylcarbonate,naphthylcarbonate, dichloro-naphthylcarbonate and others. The polymersubstrate mentioned above, which comprises polycarbonates orpolycarbonate blends is a polycarbonate-copolymer, whereinisophthalate/terephthalate-resorcinol segments are present. Suchpolycarbonates are commercially available. Other polymeric substrates ofcomponent b) may additionally contain in the form as admixtures or ascopolymers a wide variety of synthetic polymers including polyolefins,polystyrenes, polyesters, polyethers, polyamides, poly(meth)acrylates,thermoplastic polyurethanes, polysulphones, polyacetals and PVC,including suitable compatibilizing agents. For example, the polymersubstrate may additionally contain thermoplastic polymers selected fromthe group of resins consisting of polyolefins, thermoplasticpolyurethanes, styrene polymers and copolymers thereof. Specificembodiments include polypropylene (PP), polyethylene (PE), polyamide(PA), polybutylene terephthalate (PBT), polyethylene terephthalate(PET), glycol-modified polycyclohexylenemethylene terephthalate (PCTG),polysulphone (PSU), polymethylmethacrylate (PMMA), thermoplasticpolyurethane (TPU), acrylonitrile-butadiene-styrene (ABS),acrylonitrile-styrene-acrylic ester (ASA),acrylonitrile-ethylene-propylene-styrene (AES), styrene-maleic anhydride(SMA) or high impact polystyrene (HIPS).

(23) Epoxy resins consisting of di- or polyfunctional epoxide compounds.

Suitable hardener components are, for example, amine and anhydridehardeners such as polyamines, e.g., ethylenediamine, diethylenetriamine,triethylenetriamine, hexamethylenediamine, methanediamine, N-aminoethylpiperazine, diaminodiphenylmethane [DDM], alkyl-substituted derivativesof DDM, isophoronediamine [IPD], diaminodiphenylsulphone [DDS],4,4′-methylenedianiline [MDA], or m-phenylenediamine [MPDA]),polyamides, alkyl/alkenyl imidazoles, dicyandiamide [DICY],1,6-hexamethylene-bis-cyanoguanidine, or acid anhydrides, e.g.dodecenylsuccinic acid anhydride, hexahydrophthalic acid anhydride,tetrahydrophthalic acid anhydride, phthalic acid anhydride, pyromelliticacid anhydride, and derivatives thereof.

As described herein, the flame-retardant compositions of this disclosurecan be processed via mixing to incorporate the flame retardantcomposition of this disclosure into the polymer melt and then extrusionand pelletization to give pellets as products.

After thoroughly drying the pellets fabricated by the above-mentionedmethod to eliminate moisture, injection molding can be carried outaccording to the following method.

That is to say, there is no particular limitation on the injectionmolding method, and it suffices that injection molding methods, such as,representatively, general injection molding method for thermoplasticresin, gas assist molding method, and injection compression moldingmethod, can be adopted. In addition to the methods mentioned above,in-mold method, gas press molding method, two-color molding method,sandwich molding method, and the like can also be adopted according toother purposes.

The injection molding device can be constructed from a generalinjection-molding machine, a gas assist molding machine, an injectioncompression molding machine, and the like, and a molding die andauxiliary instruments, a mold temperature regulator and a sourcematerials drier, and the like that are used therefor; however, it is notlimited to such constructions.

For molding conditions, it is preferred to carry out molding with amolten resin temperature in the range of 170° C. to 210° C. to avoidthermal decomposition of the resin inside the injection cylinder.

If the injection molded article is to be obtained in a non-crystallinestate, it is preferred that the mold temperature be as low a temperatureas possible from the perspective of shortening the cooling time in themolding cycle (mold closing, injection, packing-holding, cooling, moldopening, and release). In general, 15° C. to 55° C. is desirable, aswell as the use of a chiller. However, a temperature range of 20° C. to40° C. is advantageous from the perspective of preventing contraction,warp, and deformation of the molded article.

It is effective to carry out crystallization by heating to furtherincrease the heat resistance of the molded article obtained by injectionmolding.

Examples of crystallization methods include methods wherein injectionmolding is carried out in a mold whose temperature was raised previouslyand crystallization is carried out inside the mold, methods wherein thetemperature of the mold is raised after injection molding to carry outcrystallization inside the mold, or methods wherein, after releasing theinjection molded article in a non-crystalline state, crystallization iscarried out with hot air, vapor, hot water, a far-infrared radiationheater, an IH heater, and the like. In so doing, the injection moldedarticle need not be immobilized; however, to prevent deformation of themolded article, it is preferred to immobilize the article with a metalmold, a resin mold, and the like. In addition, taking productivity intoconsideration, heating can also be carried out in a packaged state.

To carry out crystallization inside the mold, it is preferred that theinterior of a heated mold be filled with molten resin, which is thenheld inside the mold for a given time period.

In so doing, the mold temperature is from 80° C. to 130° C., andpreferably from 90° C. to 120° C.; the cooling time is from 1 to 300seconds, and preferably from 5 to 30 seconds. The heat resistance of theinjection molded article according to the present embodiment can befurther increased by carrying out crystallization inside the mold withsuch temperature and cooling time.

If crystallization is to be carried out after releasing the moldedarticle from the mold, the heating temperature is preferably in therange of 60° C. to 130° C., and more preferably in the range of 70° C.to 90° C. If the heating temperature is lower than 60° C., there is thepossibility that crystallization does not proceed in the moldingprocess, and if it is greater than 130° C., there is the possibilitythat a deformation and a contraction occur during cooling of the moldedarticle.

It is preferred that the heating time be suitably determined accordingto the composition and heating temperature. For instance, it ispreferred that at 70° C., heating be carried out for 15 minutes to 5hours. At 130° C., it is preferred that heating be carried out for 10seconds to 30 minutes.

The injection molded articles not only have excellent flame-retardantproperties, but also combine excellent impact resistance and heatresistance. That is to say, these injection molded articles have theproperties of not less than 5 kJ/m², preferably not less than 10 kJ/m²Izod impact strength according to JIS K 7110 (ASTM D256), not less than50° C., preferably not less than 55° C. deflection temperature underload according to JIS K 7191 (ASTM D648), and not less than V-2 flameretardant rating according to UL94 vertical firing test.

As the flame retardant injection molded articles described herein notonly have excellent flame-retardant properties, but also combineexcellent impact resistance and heat resistance, they can be used asconstruction materials, home appliance products, office equipment,automotive parts, and other general molded articles, and, in particular,they can also be used in applications requiring heat resistance.

In another embodiment, the flame retardant compositions of thisdisclosure comprising a polymer and a flame retardant composition can befoamed or unfoamed compositions.

Examples of polymers that can be used are foamed or unfoamed styrenepolymers, including ABS, ASA, SAN, AMSAN, polyesters, polyimides,polysulfones, polyolefins, such as polyethylene and polypropylene,polyacrylates, polyether ether ketones, polyurethanes, polycarbonates,polyphenylene oxides, unsaturated polyester resins, phenolic resins,polyamides, polyether sulfones, polyether ketones, and polyethersulfides, respectively individually or in a mixture in the form ofpolymer blends.

Preference is given to foamed or unfoamed styrene homopolymers andfoamed or unfoamed styrene copolymers, respectively individually or in amixture in the form of polymer blends.

The density of the flame-retardant polymer foams is preferably in therange from 5 to 150 kg/m³, particularly preferably in the range from 10to 50 kg/m³. The closed-cell content of the foams is preferably morethan 80%, particularly preferably from 90 to 100%.

The flame-retardant, expandable styrene polymers (EPS) and extrudedstyrene polymer foams (XPS) of this disclosure can be processed viamixing to incorporate a blowing agent and the flame retardant of thisdisclosure into the polymer melt and then extrusion and pelletizationunder pressure to give expandable pellets (EPS), or via extrusion anddepressurization, using appropriately shaped dies, to give foam sheets(XPS) or foam extrudates.

The molar mass M_(w) of expandable styrene polymers is preferably in therange from 120 000 to 400 000 g/mol, particularly preferably in therange from 180 000 to 300 000 g/mol, measured by means of gel permeationchromatography with refractiometric detection (RI) against polystyrenestandards. The molar mass of the expandable polystyrene is generallybelow the molar mass of the polystyrene used by about 10 000 g/mol,because of the molar mass degradation due to shear and/or the effect oftemperature.

Styrene polymers preferably used comprise glassclear polystyrene (GPPS),high-impact polystyrene (HIPS), anionically polymerized polystyrene orhigh-impact polystyrene (AIPS), styrene-alpha-methylstyrene copolymers,acrylonitrile-butadiene-styrene polymers (ABS), styrene-acrylonitrilecopolymers (SAN), acryl onitrile-alpha-methyl styrene copolymers(AMSAN), acrylonitrile-styrene-acrylate (ASA), methylacrylate-butadiene-styrene (MBS), methylmethacrylate-acrylonitrile-butadiene-styrene (MABS) polymers, or amixture thereof, or a mixture with polyphenylene ether (PPE).

In order to improve mechanical properties or thermal stability, thestyrene polymers mentioned may be blended with thermoplastic polymers,such as polyamides (PA), polyolefins, such as polypropylene (PP) orpolyethylene (PE), polyacrylates, such as polymethyl methacrylate(PMMA), polycarbonate (PC), polyesters, such as polyethyleneterephthalate (PET) or polybutylene terephthalate (PBT), polyethersulfones (PES), polyether ketones or polyether sulfides (PES) or amixture of these, generally in total proportions of up to a maximum of30% by weight, preferably in the range from 1 to 10% by weight, based onthe polymer melt, optionally with use of compatibilizers. Mixtureswithin the ranges of amounts mentioned are also possible with, by way ofexample, hydrophobically modified or functionalized polymers oroligomers, rubbers, such as polyacrylates or polydienes, e.g.,styrene-butadiene block copolymers, or biodegradable aliphatic oraliphatic/aromatic copolyesters.

Examples of suitable compatibilizers are maleic-anhydride-modifiedstyrene copolymers, polymers containing epoxy groups, and organosilanes.

The styrene polymer melt comprising blowing agent generally comprisesone or more blowing agents homogeneously distributed in a totalproportion of from 2 to 10% by weight, preferably from 3 to 7% byweight, based on the styrene polymer melt comprising blowing agent.Suitable blowing agents are the physical blowing agents usually used inEPS, such as aliphatic hydrocarbons having from 2 to 7 carbon atoms,alcohols, ketones, ethers, or halogenated hydrocarbons. Preference isgiven to use of isobutane, n-butane, isopentane, n-pentane. For XPS, itis preferable to use CO₂ or a mixture thereof with alcohols and/or withC₂-C₄ carbonyl compounds, in particular with ketones.

To improve foamability, finely dispersed droplets of internal water maybe introduced into the styrene polymer matrix. An example of the methodfor this is the addition of water into the molten styrene polymermatrix. The location of addition of the water may be upstream of,together with, or downstream of, the blowing agent feed. Homogeneousdistribution of the water may be achieved by using dynamic or staticmixers. An adequate amount of water, based on the styrene polymer, isgenerally from 0 to 2% by weight, preferably from 0.05 to 1.5% byweight.

The amount added of blowing agent and of water is selected in such a waythat the expansion capability a of the expandable styrene polymers(EPSs), defined as bulk density prior to foaming/bulk density afterfoaming, is at most 125, preferably from 15 to 100.

The bulk density of the expandable styrene polymer pellets (EPSs) isgenerally at most 700 g/l, preferably in the range from 590 to 660 g/l.If fillers are used, bulk densities in the range from 590 to 1200 g/lmay arise, depending on the nature and amount of the filler.

Additives, nucleating agents, fillers, plasticizers, soluble andinsoluble inorganic and/or organic dyes and pigments, e.g. athermanoussubstances, i.e., IR absorbers, such as carbon black, graphite oraluminum powder may moreover be added, together or with spatialseparation, to the styrene polymer melt, e.g. by way of mixers orancillary extruders. The amounts added of the dyes and pigments aregenerally in the range from 0.01 to 30 parts by weight, preferably inthe range from 1 to 5 parts by weight. For homogeneous and microdispersedistribution of the pigments within the styrene polymer, it can beadvantageous, particularly in the case of polar pigments, to use adispersing agent, e.g., organosilanes, polymers containing epoxy groups,or maleic-anhydride-grafted styrene polymers. Preferred plasticizers aremineral oils and phthalates, which may be used in amounts of from 0.05to 10 parts by weight, based on the styrene polymer.

To produce the expandable styrene polymers, the blowing agent can beincorporated by mixing into the polymer melt. One possible processcomprises the following stages: a) melt production, b) mixing, c)cooling, d) transport, and e) pelletizing. Each of these stages may beexecuted using the apparatus or combinations of apparatus known fromplastics processing. Static or dynamic mixers, such as extruders, aresuitable for this mixing process. The polymer melt may be taken directlyfrom a polymerization reactor, or produced directly in the mixingextruder, or in a separate melting extruder via melting of polymerpellets. The cooling of the melt may take place in the mixing assembliesor in separate coolers. Examples of pelletizers which may be used arepressurized underwater pelletizers, a pelletizer with rotating knivesand cooling via spray-misting of temperature-control liquids, orpelletizers involving atomization. Examples of suitable arrangements ofapparatus for carrying out the process are: a) polymerizationreactor-static mixer/cooler-pelletizer, b) polymerizationreactor-extruder-pelletizer, c) extruder-static mixer-pelletizer, and d)extruder-pelletizer.

The arrangement may also have ancillary extruders for introducingadditives, e.g., solids or heat-sensitive additives.

The temperature of the styrene polymer melt comprising blowing agentwhen it is passed through the die plate is generally in the range from140 to 300° C., preferably in the range from 160 to 240° C. There is noneed for cooling down to the region of the glass transition temperature.

The die plate is heated at least to the temperature of the polystyrenemelt comprising blowing agent. It is preferable that the temperature ofthe die plate is in the range from 20 to 100° C. above the temperatureof the polystyrene melt comprising blowing agent. This prevents polymerdeposits within the dies and provides problem-free pelletization.

In order to obtain marketable pellet sizes, the diameter (D) of the dieholes at the exit from the die should be in the range from 0.2 to 1.5mm, preferably in the range from 0.3 to 1.2 mm, particularly preferablyin the range from 0.3 to 0.8 mm. This permits controlled setting ofpellet sizes below 2 mm, in particular in the range from 0.4 to 1.4 mm,even after die swell.

An illustrative process involves the following steps for the productionof expandable styrene polymers (EPS) rendered flame-retardant: a) mixingto incorporate an organic blowing agent and from 1 to 25% by weight ofthe flame retardant composition of this disclosure into the polymer meltby means of a static or dynamic mixer at a temperature of at least 150°C., b) cooling of the styrene polymer melt comprising blowing agent to atemperature of at least 120° C., c) discharge through a die plate withholes, the diameter of which at the exit from the die is at most 1.5 mm,and d) pelletization of the melt comprising blowing agent directlybehind the die plate under water at a pressure in the range from 1 to 20bar.

It is also possible to produce the expandable styrene polymers (EPS) viasuspension polymerization in aqueous suspension in the presence of theflame retardant composition of this disclosure and of an organic blowingagent.

The usual auxiliaries can be added during the suspension polymerizationprocess, examples being peroxide initiators, suspension stabilizers,blowing agents, chain-transfer agents, expansion aids, nucleatingagents, and plasticizers. The amounts of flame retardant composition ofthis disclosure added in the polymerization process are from 0.5 to 25%by weight, preferably from 5 to 15% by weight. The amounts of blowingagents added are from 3 to 10% by weight, based on monomer. Theseamounts can be added prior to, during, or after polymerization of thesuspension. Examples of suitable blowing agents are aliphatichydrocarbons having from 4 to 6 carbon atoms. It is advantageous to useinorganic Pickering dispersants as suspension stabilizers, an examplebeing magnesium pyrophosphate or calcium phosphate.

The suspension polymerization process can produce bead-shaped particleswhich are in essence round, with average diameter in the range from 0.2to 2 mm.

In order to improve processability, the finished expandable styrenepolymer pellets can be coated with glycerol ester, antistatic agent, oranticaking agent.

The EPS pellets can be coated with glycerol monostearate GMS (typically0.25%), glycerol tristearate (typically 0.25%), fine-particle silica(typically 0.12%), or Zn stearate (typically 0.15%), or else antistaticagent.

The expandable styrene polymer pellets can be prefoamed in a first stepby means of hot air or steam to give foam beads with density in therange from 5 to 150 kg/m³, in particular from 10 to 50 kg/m³, and can befused in a second step in a closed mold, to give molded particles.

The expandable polystyrene particles can be processed to givepolystyrene foams with densities of from 8 to 150 kg/m³, preferably from10 to 50 kg/m³ (measured to ISO 845). To this end, the expandable beadsare prefoamed. This is mostly achieved by heating of the beads, usingsteam in what are known as prefoamers. The resultant prefoamed beads arethen fused to give moldings. To this end, the prefoamed beads areintroduced into molds which do not have a gas-tight seal, and aretreated with steam. The moldings can be removed after cooling.

In another embodiment, the foam is an extruded polystyrene (XPS),obtainable via: a) heating of a polymer component to form a polymermelt, b) introduction of a blowing agent component into the polymer meltto form a foamable melt, c) extrusion of the foamable melt into a regionof relatively low pressure with foaming to give an extruded foam, and d)addition of the flame retardant composition of this disclosure and also,optionally, of further auxiliaries and additives, in at least one of thesteps a) and/or b).

Foams based on styrene polymers, in particular EPS and XPS, are suitableby way of example for use as insulation materials, in particular in theconstruction industry.

As described above, the compositions according to this disclosure mayadditionally contain one or more conventional additives, for exampleselected from pigments, dyes, plasticizers, antioxidants, surfactants,adsorbents, binders, suppressants, detergents, dispersants, wettingagents, emulsifiers, foaming agents, viscosity modifiers, corrosioninhibitors, thixotropic agents, leveling assistants, basicco-stabilizers, metal passivators, metal oxides, organophosphoruscompounds, further light stabilizers and mixtures thereof, especiallypigments, phenolic antioxidants, calcium stearate, zinc stearate, UVabsorbers of the 2-hydroxy-benzophenone,2-(2′-hydroxyphenyl)benzotriazole and/or2-(2-hydroxyphenyl)-1,3,5-triazine groups.

Illustrative pigments useful in the compositions of this disclosureinclude, for example, inorganic or organic colorants, and the like. Therecommended amount of pigment to be added will be in the range of0.1-5.0 wt % of the composition.

Illustrative dyes useful in the compositions of this disclosure include,for example, inorganic or organic colorants, and the like. Therecommended amount of dye to be added will be in the range of 0.1-5.0 wt% of the flame retardant solution.

Illustrative plasticizers useful in the compositions of this disclosureinclude, for example, diorganic phthatate, and the like. The recommendedamount of plasticizer to be added will be in the range of 0.1-12 wt % ofthe flame retardant solution.

Illustrative antioxidants useful in the compositions of this disclosureinclude, for example, gloathione, and the like. The recommended amountof antioxidant to be added will be in the range of 0.1-12 wt % of theflame retardant solution.

Illustrative surfactants useful in the compositions of this disclosureinclude, for example, alkylbenzene sulfonate, polyalkylene glycol, andthe like. The recommended amount of surfactant to be added will be inthe range of 0.5-12 wt % of the composition.

Illustrative adsorbents useful in the compositions of this disclosureinclude, for example, alumina silicate, and the like. The recommendedamount of adsorbent to be added will be in the range of 0.1-15.0 wt % ofthe flame retardant solution.

Illustrative binders useful in the compositions of this disclosureinclude, for example, copolymers of isocyanates, casein, and the like.The recommended amount of binder to be added will be in the range of10-30 wt % of the flame retardant solution.

Illustrative smoke suppressants useful in the compositions of thisdisclosure include, for example, zinc molybdate, calcium zinc molybdate,zinc oxide/phosphate complexes, and the like. The recommended amount ofsuppressant to be added will be in the range of 0.1-5.0 wt % of theflame retardant solution.

Illustrative detergents useful in the compositions of this disclosureinclude, for example, alkybenzene sulfonates, and the like. Therecommended amount of detergent to be added will be in the range of0.1-8.0 wt % of the flame retardant solution.

Illustrative dispersants useful in the compositions of this disclosureinclude, for example, sulfate, sulfonate, and phosphate esters,carboxylates, cationic head groups, Zwitterionic surfactants,ethoxylates, fatty acid esters of polyhydroxy compounds, amine oxides,sulfoxides, phosphine oxides, and the like. The recommended amount ofdispersant to be added will be in the range of 0.1-6.0 wt % of the flameretardant solution.

Illustrative wetting agents useful in the compositions of thisdisclosure include, for example, sulfosuclinate, and the like. Therecommended amount of wetting agent to be added will be in the range of0.1-6.0 wt % of the flame retardant solution.

Illustrative emulsifiers useful in the compositions of this disclosureinclude, for example, lauryl PEG-9 polydimethylsuloxyethyl dimethicone,alkybenzene sulfonates, polysorbates, sodium phosphates, sodium stearoyllactylate, and the like. The recommended amount of emulsifier to beadded will be in the range of 0.1-6.0 wt % of the flame retardantsolution.

Illustrative foaming agents useful in the compositions of thisdisclosure include, for example, lauryl sulfate, and the like. Therecommended amount of foaming agent to be added will be in the range of0.1-6.0 wt % of the flame retardant solution.

Illustrative viscosity modifiers useful in the compositions of thisdisclosure include, for example, carboxymethylcellulose powder, acaciagum, beeswax, and the like. The recommended amount of viscosity modifierto be added will be in the range of 0.1-6.0 wt % of the flame retardantsolution.

Illustrative corrosion inhibitors useful in the compositions of thisdisclosure include, for example, zinc borate, and the like. Therecommended amount of corrosion inhibitor to be added will be in therange of 0.1-15 wt % of the flame retardant solution.

Illustrative thixotropic agents useful in the compositions of thisdisclosure include, for example, fumed silica, and the like. Therecommended amount of thixotropic agent to be added will be in the rangeof 0.1-15 wt % of the flame retardant solution.

Illustrative leveling assistants useful in the compositions of thisdisclosure include, for example, decahydrated sodium sulfates, and thelike. The recommended amount of leveling assistant to be added will bein the range of 0.1-6.0 wt % of the flame retardant solution.

Illustrative stabilizers useful in the compositions of this disclosureinclude, for example, butylated hydoxytoluene, and the like. Therecommended amount of stabilizer to be added will be in the range of0.1-15.0 wt % of the flame retardant solution.

Illustrative stabilizers useful in the compositions of this disclosureinclude, for example, butylated hydroxytoluene, and the like. Thestabilizers include light stabilizers, for example hindered amine, andthe like. The recommended amount of stabilizer to be added will be inthe range of 0.1-15.0 wt % of the flame retardant solution.

Illustrative metal passivators useful in the compositions of thisdisclosure include, for example, nitric acid, and the like. Therecommended amount of metal passivator to be added will be in the rangeof 0.1-15.0 wt % of the flame retardant solution.

Illustrative metal oxides useful in the compositions of this disclosureinclude, for example, zinc oxide, magnesium oxide, aluminum oxide,calcium oxide, sodium oxide, potassium oxide, antimony oxide, and thelike. The recommended amount of metal oxide to be added will be in therange of 0.1-35.0 wt % of the flame retardant solution.

Illustrative organophosphorus compounds useful in the compositions ofthis disclosure include, for example, triazine polyphosphate esters, andthe like. The recommended amount of organophosphorus compound to beadded will be in the range of 0.1-30 wt % of the flame retardantsolution.

The compositions of this disclosure can optionally include a solvent.The solvent can be any solvent suitable for use in the compositions ofthis disclosure. Illustrative solvents include, for example, organicsolvents such as an aromatic compound, alcohol, ester, ether, ketone,amine, nitrated hydrocarbon, halogenated hydrocarbon, and the like. Therecommended amount of solvent to be added will be in the range of 1-15wt % of the flame retardant solution.

The incorporation of the ingredients or components described herein intothe substrate material or component (e.g., polymer component) is carriedout by known methods such as dry blending in the form of a powder, orwet mixing in the form of solutions, dispersions or suspensions forexample in an inert solvent, water or oil. The additive components maybe incorporated, for example, before or after molding or also byapplying the dissolved or dispersed additive or additive mixture to thepolymer material, with or without subsequent evaporation of the solventor the suspension/dispersion agent. They may be added directly into theprocessing apparatus (e.g. extruders, internal mixers, etc.), e.g., as adry mixture or powder, or as a solution or dispersion or suspension ormelt.

The addition of the additive components to the substrate material (e.g.,polymer substrate) can be carried out in customary mixing machines inwhich the polymer is melted and mixed with the additives. Suitablemachines are known to those skilled in the art. They are predominantlymixers, kneaders and extruders.

In an embodiment, the process is carried out in an extruder byintroducing the additive during processing.

Particularly useful processing machines are single-screw extruders,contra-rotating and co-rotating twin-screw extruders, planetary-gearextruders, ring extruders or co-kneaders. Processing machines providedwith at least one gas removal compartment can be used to which a vacuumcan be applied.

For example, the screw length is 1-60 screw diameters, preferably 35-48screw diameters. The rotational speed of the screw is preferably 10-600rotations per minute (rpm), preferably 25-300 rpm.

The maximum throughput is dependent on the screw diameter, therotational speed and the driving force. The process can also be carriedout at a level lower than maximum throughput by varying the parametersmentioned or employing weighing machines delivering dosage amounts.

If a plurality of components is added, these can be premixed or addedindividually.

The additive components can also be sprayed onto the polymer substrate.The additive mixture dilutes other additives, for example theconventional additives indicated above, or their melts so that they canbe sprayed also together with these additives onto the polymersubstrate. Addition by spraying during the deactivation of thepolymerization catalysts is particularly advantageous; in this case, thesteam evolved may be used for deactivation of the catalyst. In the caseof spherically polymerized polyolefins it may, for example, beadvantageous to apply the additives by spraying.

The additive components can also be added to the polymer in the form ofa master batch (“concentrate”) which contains the components in aconcentration of, for example, about 1.0% to about 40.0% and preferably2.0% to about 20.0% by weight incorporated in a polymer. The polymer isnot necessarily of identical structure than the polymer where theadditives are added finally. In such operations, the polymer can be usedin the form of powder, granules, solutions, and suspensions or in theform of lattices.

Incorporation can take place prior to or during the shaping operation.The materials containing the additives described herein preferably areused for the production of molded articles, for example roto-moldedarticles, injection molded articles, profiles and the like, andespecially a fiber, spun melt non-woven, film or foam.

In an embodiment, this disclosure provides a process for imparting flameretardancy to a substrate material. The process comprises adding to asubstrate material a flame retardant composition. The flame retardantcomposition comprises at least one flame retardant salt, anitrogen-containing compound, and optionally water.

The flame retardant compositions of this disclosure can be used in avariety of products, in particular, four major areas includingelectronics and electrical devices, building and construction materials,furnishings, and transportation (e.g., airplanes, trains, motor vehiclesand marine transportation).

Illustrative electronics and electrical devices include, for example,television and other electronic device casings; computers and laptops,including monitors, keyboards and portable digital devices; telephonesand cell phones; refrigerators; washers and dryers; vacuum cleaners;electronic circuit boards; electrical and optical wires and cables;small household appliances; battery chargers; and the like.

Illustrative building and construction materials include, for example,electrical wires and cables, including those behind walls; insulationmaterials (e.g., polystyrene and polyurethane insulation foams); paintsand coatings which are applied to a variety of building materials,including steel structures, metal sheets, wood, plaster and concrete;structural and decorative wood products; roofing components; compositepanels; decorative fixtures; and the like

Illustrative furnishings include, for example, natural and syntheticfilling materials and textile fibers; foam upholstery; foam mattresses;curtains and fabric blinds; carpets; and the like.

Illustrative transportation (airplanes, trains, automobiles) includes,for example, overhead compartments; seat covers and fillings; seats,headrests and armrests; roof liners; textile carpets; curtains; sidewalland ceiling panels; internal structures, including dashboards andinstrument panels; insulation panels; electrical and electronic cablecoverings; electrical and electronic equipment; battery cases and trays;car bumpers; stereo components; GPS and other computer systems; and thelike.

Preferred embodiments of this disclosure include are described in thefollowing clauses:

1. A composition comprising one or more substrate materials and a flameretardant composition, said flame retardant composition comprising atleast one flame retardant salt, a nitrogen-containing compound, andoptionally water.

2. The composition of clause 1 wherein the at least one flame retardantsalt comprises an ammonium salt of phosphoric acid, and thenitrogen-containing compound comprises urea.

3. The composition of clause 2 wherein the ammonium salt of phosphoricacid comprises water soluble ammonium polyphosphate (APP).

4. The composition of clause 3 wherein the ammonium salt of phosphoricacid comprises water soluble ammonium polyphosphate (APP), ammoniumdihydrogen phosphate (MAP), and di-ammonium hydrogen phosphate (DAP).

5. The composition of clause 1 wherein the at least one flame retardantsalt comprises an ammonium salt of phosphoric acid and an ammonium saltof bromine; and the nitrogen-containing compound comprises urea.

6. The composition of clause 5 wherein the ammonium salt of phosphoricacid comprises water soluble ammonium polyphosphate (APP), and theammonium salt of bromine comprises ammonium bromide.

7. The composition of clause 3 wherein the water soluble ammoniumpolyphosphate has a total nitrogen as N from about 5 to about 15 weightpercent, and a total phosphorus as P₂O₅ from about 30 to about 40 weightpercent, based on the total weight of the ammonium polyphosphate.

8. The composition of clause 3 wherein the water soluble ammoniumpolyphosphate has a density from about 1.75 to about 1.90 g/cm³, a watersolubility of greater than about 60 g/100 ml, and a pH from about 6.5 toabout 8.5.

9. The composition of clause 1 comprising from about 10 to about 90weight percent of the at least one flame retardant salt, and from about10 to about 60 weight percent of the at least one nitrogen-containingcompound; wherein the entirety of the components is 100 weight percent.

10. The composition of clause 1 comprising from about 10 to about 90weight percent of the at least one flame retardant salt, from about 10to about 60 weight percent of the at least one nitrogen-containingcompound, and from about 1 to about 95 weight percent of water; whereinthe entirety of the components is 100 weight percent.

11. The composition of clause 1 wherein the substrate material is atleast one selected from the group consisting of electronics orelectrical devices, building or construction materials, furnishings,clothing, and transportation.

12. The composition of clause 1 wherein the substrate material is atleast one material selected from the group consisting of: polymers,rubbers, paper pulps, textiles, foams, metals, lumber, concrete, stone,paints, adhesives, and nano particles.

13. The composition of clause 12 wherein the polymer comprises athermoplastic polymer or a thermoset polymer; wherein the thermoplasticpolymer is at least one selected from the group consisting of: highimpact polystyrene, polyphenylene ethers, polyamides, polyesters,polycarbonates, polyolefins, polyethers, and blends or polyblends of thetype represented by ABS (acrylonitrile-butadiene-styrene) or PC/ABS(polycarbonate/acrylonitrile-butadiene-styrene), polyamide, polyester,polyarylates, polymethacrylates, or ABS; and wherein the thermosetpolymer is at least one selected from the group consisting of:formaldehyde, epoxy, melamine, or phenolic resin polymers, andpolyurethanes.

14. The composition of clause 1 wherein the substrate material ispresent in an amount from about 5 weight percent to about 95 weightpercent, and the flame retardant composition is present in an amountfrom about 5 weight percent to about 95 weight percent, wherein theentirety of the components is 100 weight percent.

15. The composition of clause 1 wherein the flame retardant compositionis sprayed onto the substrate material, impregnated into the substratematerial, the substrate material is dipped into the flame retardantcomposition, or the flame retardant is added to a fiber yarn.

16. The composition of clause 1 further comprising at least one additiveselected from the group consisting of a pigment, a dye, a plasticizer,an antioxidant, a surfactant, a dispersant, a detergent, a wettingagent, an emulsifier, an adsorbent, a binder, a suppressant, athixotropic agent, a leveling assistant, a basic co-stabilizer, a metalpassivator, a metal oxide, an organophosphorus compound, a corrosioninhibitor, a foaming agent, a viscosity modifier, and a lightstabilizer.

17. The composition of clause 1 further comprising at least one additiveselected from the group consisting of alum (hydrated potassium aluminumsulfate), sodium stannate, sodium or potassium silicate (liquid glass),sodium borate (borax), carboxymethyl cellulose, starch-like compound,organophosphorus nitrogen compound, glycerin or glycerol, isocyanate,polyurethane, organosilicone, pentaerythitol, and 4A natural zeolite.

18. The composition of clause 1 further comprising a solvent.

19. The composition of clause 18 wherein the solvent is at least oneselected from the group consisting of aromatic compounds, alcohols,esters, ethers, ketones, amines, nitrated hydrocarbons, and halogenatedhydrocarbons.

20. The composition of clause 1 which is a powder, solution, dispersion,suspension, or melt.

21. A composition comprising one or more substrate materials and a flameretardant composition, said flame retardant composition comprising atleast one flame retardant salt, a nitrogen-containing compound, andoptionally water; wherein the at least one flame retardant saltcomprises water soluble ammonium polyphosphate (APP); and thenitrogen-containing compound comprises urea.

22. A composition comprising one or more substrate materials and a flameretardant composition, said flame retardant composition comprising atleast one flame retardant salt, a nitrogen-containing compound, andoptionally water; wherein the at least one flame retardant saltcomprises water soluble ammonium polyphosphate (APP), ammoniumdihydrogen phosphate (MAP), and di-ammonium hydrogen phosphate (DAP);and the nitrogen-containing compound comprises urea.

23. A composition comprising one or more substrate materials and a flameretardant composition, said flame retardant composition comprising atleast one flame retardant salt, a nitrogen-containing compound, andoptionally water; wherein the at least one flame retardant saltcomprises water soluble ammonium polyphosphate (APP) and ammoniumbromide; and the nitrogen-containing compound comprises urea.

24. A composition comprising one or more substrate materials and a flameretardant composition, said flame retardant composition comprising atleast one flame retardant salt, optionally a nitrogen-containingcompound, and optionally water; wherein the at least one flame retardantsalt comprises water soluble ammonium polyphosphate (APP).

25. A flame retardant composition comprising at least one flameretardant salt, optionally a nitrogen-containing compound, andoptionally water, wherein the at least one flame retardant saltcomprises water soluble ammonium polyphosphate (APP), and wherein thewater soluble ammonium polyphosphate (APP) has a density from about 1.75to about 1.90 g/cm³, a water solubility of greater than about 60 g/100ml, a pH from about 6.5 to about 8.5, and a total nitrogen as N fromabout 5 to about 15 weight percent, and a total phosphorus as P₂O₅ fromabout 30 to about 40 weight percent, based on the total weight of theammonium polyphosphate (APP).

26. The flame retardant composition of clause 25 further comprising atleast one additive selected from the group consisting of a pigment, adye, a plasticizer, an antioxidant, a surfactant, a dispersant, adetergent, a wetting agent, an emulsifier, an adsorbent, a binder, asuppressant, a thixotropic agent, a leveling assistant, a basicco-stabilizer, a metal passivator, a metal oxide, an organophosphoruscompound, a corrosion inhibitor, a foaming agent, a viscosity modifier,and a UV light stabilizer.

27. The flame retardant composition of clause 25 further comprising atleast one additive selected from the group consisting of alum (hydratedpotassium aluminum sulfate), sodium stannate, sodium or potassiumsilicate (liquid glass), sodium borate (borax), carboxymethyl cellulose,starch-like compound, organophosphorus nitrogen compound, glycerin orglycerol, isocyanate, polyurethane, organosilicone, pentaerythitol, and4A natural zeolite.

28. The flame retardant composition of clause 27 further comprising asolvent.

29. The flame retardant composition of clause 28 wherein the solvent isat least one selected from the group consisting of aromatic compounds,alcohols, esters, ethers, ketones, amines, nitrated hydrocarbons, andhalogenated hydrocarbons.

30. The flame retardant composition of clause 25 which is a powder,solution, dispersion, suspension, melt, gel, or grease.

31. An article formed from a composition comprising one or moresubstrate materials and a flame retardant composition, said flameretardant composition comprising at least one flame retardant salt, anitrogen-containing compound, and optionally water, wherein said articlecomprises (i) a polymer article selected from the group consisting of apolymer molding, a polymer film, a polymer filament and a polymer fiber;or (ii) an extrusion article formed by extrusion, injection molding, ora combination thereof.

32. The article of clause 31 wherein the at least one flame retardantsalt comprises water soluble ammonium polyphosphate (APP), and thenitrogen-containing compound comprises urea.

33. A process for the production of an extruded article, said processcomprising:

heating a polymer to form a polymer melt;

adding a flame retardant powder composition to the polymer melt to forma flame retardant polymer melt, said flame retardant compositioncomprising at least one flame retardant salt, and a nitrogen-containingcompound; and

extruding the flame retardant polymer melt to give an extruded article.

34. The process of clause 33 wherein the at least one flame retardantsalt comprises water soluble ammonium polyphosphate (APP), and thenitrogen-containing compound comprises urea.

35. An extrudable composition comprising a flame retardant polymer melt,wherein the flame retardant polymer melt comprises a polymer melt and aflame retardant composition, said flame retardant composition comprisingat least one flame retardant salt, a nitrogen-containing compound, andoptionally one or more metals.

36. The extrudable composition of clause 35 wherein the metal isaluminum.

37. A process for imparting flame retardancy to a substrate material,said process comprising:

adding to a substrate material a flame retardant composition, said flameretardant composition comprising at least one flame retardant salt, anitrogen-containing compound, and optionally water.

38. The process of clause 37 wherein the at least one flame retardantsalt comprises water soluble ammonium polyphosphate (APP), and thenitrogen-containing compound comprises urea.

39. A process for preparing a flame retardant composition, said processcomprising:

adding to a container at least one flame retardant salt, anitrogen-containing compound, and optionally water; and

mixing the contents of the container to give a dispersed mixture ordissolved solution comprising the flame retardant composition.

40. The process of clause 39 wherein the at least one flame retardantsalt comprises water soluble ammonium polyphosphate (APP), and thenitrogen-containing compound comprises urea.

41. An intumescent process for forming an insulating protective layer ona substrate, said process comprising:

providing a flame retardant composition comprising at least one flameretardant salt, a nitrogen-containing compound, and optionally water;wherein the at least one flame retardant salt comprises an ammonium saltof phosphoric acid, and the nitrogen-containing compound comprises urea;

heating the ammonium salt of phosphoric acid to give an inorganic acid;

carbonizing the inorganic acid with a polyalcohol present in thesubstrate;

hydrolyzing the urea to give ammonia and reacting the ammonia to givenitrogen gas;

foaming the mixture of the carbonized inorganic acid and the nitrogengas; and

solidifying the foam through one or more cross linking reactions to formthe insulating protective layer on the substrate.

42. The process of clause 41 wherein the at least one flame retardantsalt comprises water soluble ammonium polyphosphate (APP).

The following non-limiting examples are provided to illustrate thedisclosure.

EXAMPLES

Comparative Flame Retardant Composition

A comparative flame retardant composition was prepared having thefollowing ingredients in the indicated amounts: ammonium dihydrogenphosphate (MAP) (10-20 wt %); di-ammonium hydrogen phosphate (DAP)(10-20 wt %); ammonium bromide (30-50 wt %); ammonium sulfate (10-20 wt%); and urea (10-20 wt %).

In testing, the comparative flame retardant composition cannot withstandany washing (especially on cotton). The comparative flame retardantcomposition exhibited clumping, and became jelly-like after storage forlong time (e.g., months). In testing on a textile, particles of thecomparative flame retardant composition dropped off from treatedtextiles upon shaking. The comparative flame retardant composition iscorrosive to metals.

Flame Retardant Composition of this Disclosure

A flame retardant composition of this disclosure was prepared having thefollowing ingredients in the indicated amounts: water soluble ammoniumpolyphosphate (APP) (40-60 wt %); ammonium dihydrogen phosphate (MAP)(10-25 wt %); di-ammonium hydrogen phosphate (DAP) (10-25 wt %); andurea (10-25 wt %).

In testing, the flame retardant composition of this disclosure did notexhibit clumping, and did not become jelly-like after storage for longtime (e.g., months). In testing on a textile, particles of the flameretardant composition of this disclosure did not drop off from treatedtextiles upon shaking. The flame retardant composition of thisdisclosure is not corrosive to metals.

Other Flame Retardant Compositions of this Disclosure

A flame retardant composition of this disclosure was prepared having thefollowing ingredients in the indicated amounts: water soluble ammoniumpolyphosphate (APP) (40-60 wt %); ammonium dihydrogen phosphate (MAP)(10-25 wt %); di-ammonium hydrogen phosphate (DAP) (10-25 wt %);ammonium bromide (10-25 wt %); ammonium sulfate (10-25 wt %);carboxymethyl cellulose (CMC) (1-10 wt %); sodium borate (borax) (1-10wt %); sodium silicate (1-10 wt %); and urea (10-25 wt %).

Another flame retardant composition of this disclosure was preparedhaving the following ingredients in the indicated amounts: water solubleammonium polyphosphate (APP) (40-60 wt %); ammonium dihydrogen phosphate(MAP) (10-25 wt %); di-ammonium hydrogen phosphate (DAP) (10-25 wt %);ammonium chloride (10-25 wt %); hydrated potassium aluminum sulfate(alum) (10-25 wt %); carboxymethyl cellulose (CMC) (1-10 wt %); sodiumborate (borax) (1-10 wt %); sodium silicate (1-10 wt %); and urea (10-25wt %).

In testing, the above other flame retardant compositions of thisdisclosure exhibited improved thermal protection performance (TPP)versus the comparative flame retardant composition.

A flame retardant composition of this disclosure was prepared having thefollowing ingredients in the indicated amounts: water soluble ammoniumpolyphosphate (APP) (40-60 wt %); ammonium sulfate (10-25 wt %);starch-like compounds (cassava liquid, sweet potato, tapioca extract orcatalase) (10-25 wt %); sodium borate (borax) (1-10 wt %); sodiumsilicate (1-10 wt %); and sodium stannate (1-10 wt %).

Another flame retardant composition of this disclosure was preparedhaving the following ingredients in the indicated amounts: water solubleammonium polyphosphate (APP) (40-60 wt %); hydrated potassium aluminumsulfate (alum) (10-25 wt %); starch-like compounds (cassava liquid,sweet potato, tapioca extract or catalase) (10-25 wt %); and ammoniumdihydrogen phosphate (MAP) (10-25 wt %).

In testing, the above other flame retardant compositions of thisdisclosure exhibited improved retention of flame retardancy afternumerous cycles of washing versus the comparative flame retardantcomposition.

The chemical composition of the flame retardant of this disclosureindicates multiple mechanisms of flame retardation including inert gasdilution (ammonia), chemical interaction (bromide), and a protectivelayer (phosphate). These mechanisms of flame retardation are supportedby the observed material behavior during a controlled burn test.

All patents and patent applications, test procedures (such as ASTMmethods, UL methods, and the like), and other documents cited herein arefully incorporated by reference to the extent such disclosure is notinconsistent with this disclosure and for all jurisdictions in whichsuch incorporation is permitted.

When numerical lower limits and numerical upper limits are listedherein, ranges from any lower limit to any upper limit are contemplated.While the illustrative embodiments of the disclosure have been describedwith particularity, it will be understood that various othermodifications will be apparent to and can be readily made by thoseskilled in the art without departing from the spirit and scope of thedisclosure. Accordingly, it is not intended that the scope of the claimsappended hereto be limited to the examples and descriptions set forthherein but rather that the claims be construed as encompassing all thefeatures of patentable novelty which reside in the present disclosure,including all features which would be treated as equivalents thereof bythose skilled in the art to which the disclosure pertains.

While we have shown and described several embodiments in accordance withour disclosure, it is to be clearly understood that the same may besusceptible to numerous changes apparent to one skilled in the art.Therefore, we do not wish to be limited to the details shown anddescribed but intend to show all changes and modifications that comewithin the scope of the appended claims.

What is claimed is:
 1. A composition comprising one or more substratematerials and a flame retardant composition, said flame retardantcomposition comprising at least one flame retardant salt, anitrogen-containing compound, and optionally water; wherein the at leastone flame retardant salt comprises an ammonium salt of phosphoric acid;wherein the ammonium salt of phosphoric acid comprises water solubleammonium polyphosphate (APP); wherein the water soluble ammoniumpolyphosphate has a total nitrogen as N from about 5 to about 15 weightpercent, and a total phosphorus as P₂O₅ from about 30 to about 40 weightpercent, based on the total weight of the ammonium polyphosphate (APP).2. The composition of claim 1 wherein the nitrogen-containing compoundcomprises urea.
 3. The composition of claim 1 wherein the ammonium saltof phosphoric acid further comprises ammonium dihydrogen phosphate (MAP)and di-ammonium hydrogen phosphate (DAP).
 4. The composition of claim 1wherein the at least one flame retardant salt further comprises anammonium salt of bromine; and the nitrogen-containing compound comprisesurea.
 5. The composition of claim 4 wherein the ammonium salt of brominecomprises ammonium bromide.
 6. The composition of claim 1 wherein thewater soluble ammonium polyphosphate has a density from about 1.75 toabout 1.90 g/cm³, a water solubility of greater than about 60 g/100 ml,and a pH from about 6.5 to about 8.5.
 7. The composition of claim 1comprising from about 10 to about 90 weight percent of the at least oneflame retardant salt, and from about 10 to about 60 weight percent ofthe at least one nitrogen-containing compound; wherein the entirety ofthe components is 100 weight percent.
 8. The composition of claim 1wherein the substrate material is at least one selected from the groupconsisting of electronics or electrical devices, building orconstruction materials, furnishings, clothing, and transportation. 9.The composition of claim 1 wherein the substrate material is at leastone material selected from the group consisting of: polymers, rubbers,paper pulps, textiles, foams, metals, lumber, concrete, stone, paints,adhesives, and nano particles.
 10. The composition of claim 9 whereinthe polymer comprises a thermoplastic polymer or a thermoset polymer;wherein the thermoplastic polymer is at least one selected from thegroup consisting of: high impact polystyrene, polyphenylene ethers,polyamides, polyesters, polycarbonates, polyolefins, polyethers, andblends or polyblends of the type represented by ABS(acrylonitrile-butadiene-styrene) or PC/ABS(polycarbonate/acrylonitrile-butadiene-styrene), polyamide, polyester,polyarylates, polymethacrylates, or ABS; and wherein the thermosetpolymer is at least one selected from the group consisting of:formaldehyde, epoxy, melamine, or phenolic resin polymers, andpolyurethanes.
 11. The composition of claim 1 wherein the substratematerial is present in an amount from about 5 weight percent to about 95weight percent, and the flame retardant composition is present in anamount from about 5 weight percent to about 95 weight percent, whereinthe entirety of the components is 100 weight percent.
 12. Thecomposition of claim 1 wherein the flame retardant composition issprayed onto the substrate material, impregnated into the substratematerial, the substrate material is dipped into the flame retardantcomposition, or the flame retardant is added to a fiber yarn.
 13. Thecomposition of claim 1 further comprising at least one additive selectedfrom the group consisting of a pigment, a dye, a plasticizer, anantioxidant, a surfactant, a dispersant, a detergent, a wetting agent,an emulsifier, an adsorbent, a binder, a suppressant, a thixotropicagent, a leveling assistant, a basic co-stabilizer, a metal passivator,a metal oxide, an organophosphorus compound, a corrosion inhibitor, afoaming agent, a viscosity modifier, and a light stabilizer.
 14. Thecomposition of claim 1 further comprising at least one additive selectedfrom the group consisting of alum (hydrated potassium aluminum sulfate),sodium stannate, sodium or potassium silicate (liquid glass), sodiumborate (borax), carboxymethyl cellulose, starch-like compound,organophosphorus nitrogen compound, glycerin or glycerol, isocyanate,polyurethane, organosilicone, pentaerythitol, and 4A natural zeolite.15. The composition of claim 1 further comprising a solvent.
 16. Thecomposition of claim 1 which is a powder, solution, dispersion,suspension, or melt.
 17. A flame retardant composition comprising atleast one flame retardant salt, optionally a nitrogen-containingcompound, and optionally water, wherein the at least one flame retardantsalt comprises water soluble ammonium polyphosphate (APP), and whereinthe water soluble ammonium polyphosphate (APP) has a density from about1.75 to about 1.90 g/cm³, a water solubility of greater than about 60g/100 ml, a pH from about 6.5 to about 8.5, and a total nitrogen as Nfrom about 5 to about 15 weight percent, and a total phosphorus as P₂O₅from about 30 to about 40 weight percent, based on the total weight ofthe ammonium polyphosphate (APP).